Girl I did this for a year and a half. My AH LIVED with his affair partner. I kept him at arms distance, really working on myself for the four months he lived with her, until he wanted to come home. I picked myself up off the kitchen floor over and over again until I finally left. You may not have to do that. Who knows?
Please, please PLEASE be kind to yourself. These are deep emotional issues and habits you're working out. AND you've got a baby! You can do whatever you want. You wanna hang out and get attention from him. You can. You've had enough and dont' want to see what happens next wtih this guy? That's your choice too. You have choices.
You can also, if you so desire, reprogram yourself to be pleasant, but distant. You don't have to discuss anything with him, but if you don't give up one thing you'll be ok no matter what. (Ok you're going to be ok no matter what even if you don't do this one thing, but it sure will help)
Keep doing your life. If you choose to snoop, get right back you YOUR LIFE. Work on releasing the obsession. You'll sort out what that mean.
No matter what, do the self care thing that you need to do as if he weren't around and had never been. Buy new shampoo. Wash the floor. Pluck your eyebrows. Get a job you love. Hang out with the people who love you best. Who really love you best. Do not sever that cord of self love.
You're in a mess for sure. I've been there, and won't judge or harsh on you. Applying the steps should really work too. He's going to do what he does, no doubt about it.
The important question is what are you going to do? How are you going to shape your life and your childs life. Just dont' get sucked into the vortex of being obsessed with him again, because he's already got that covered.
Hugs!